How to lie with maps

Cover art from 'How to Lie With Maps'

 by Mark Monmonier, third edition 

University of Chicago Press © University of Chicago Press

From Financial Time by Alan Smith

The internet has profoundly shaped cartography, but has not made it more honest 

At the height of the 1820s boom in South American bonds, Gregor MacGregor, a veteran of Simón Bolívar’s campaigns against Spanish rule on the continent, arrived in London to sell bonds in the thriving Central American republic of Poyais.
Inevitably, a map appeared — which the Poyais-bound passengers on London’s first emigrant ships to the country must have clutched excitedly on the long journey to their new home.
Upon arrival, the fledgling country’s newest citizens found just one problem — Poyais itself didn’t exist.
Hundreds of settlers who had exchanged their life savings for a fresh start in the new world had unwittingly become victims of one of the most sophisticated confidence tricks in history.
Marooned in an uninhabited mosquito-infested swamp, most would pay with their lives.

 Detail from a map of Mosquitia and the Territory of Poyais

It’s easy to see how people were duped.
The handsome “Map of Mosquitia and the Territory of Poyais” tapped into our innate trust of maps.
If the map says so, then it must be true.
In fact all maps lie, even good ones, says professor Mark Monmonier, author of the classic book How to Lie With Maps.

Previous edition

A third edition has just been published more than two decades after the second, an intervening period in which the world wide web has profoundly reshaped the public perception and usage of maps.
A call with Mr Monmonier in his upstate New York home reveals a passion for maps undimmed by time.
Now 75, he still teaches cartographic design classes at Syracuse University’s Maxwell School.
A 2014 self-published autobiography details his journey from a 1969 PhD — one of the first doctoral dissertations to involve digital mapping — through decades of researching, teaching, writing and consulting on cartography and “spatial thinking”.
As we talk, it soon becomes clear that it is the actual impact of maps — particularly on culture, politics and science — that interests Mr Monmonier most.

 A map of Atlantis 'in its prime' from the Theosophical Publishing House of London (1896)

 

His attention-grabbing book titles (From Squaw Tit to Whorehouse Meadow: How Maps Name, Claim, and Inflame) are a clue that he wants to share his understanding of that impact far and wide. He hopes to debunk many of the myths associated with maps.
For example, the widely reported death of printed maps: “They haven’t died — they have just become more specialised.”
And unlike some map purists, he describes Google Maps as “an enormously valuable tool” both in itself, and as a platform for a variety of different mash-ups that allow people to put their own data on it.
He is even relatively lenient on Google Maps’ notorious use of the Mercator projection (which exaggerates area away from the equator, making Greenland appear as large as South America).
“It does not distort angles. This mathematical property, called conformality, allows only a minimal, largely unnoticeable distortion of local shapes and distances on individual [map] tiles at the more detailed zoom levels [Google Maps’ primary role]”.

 Graphic showing how two different map projections distort reality

© University of Chicago Press

Mr Monmonier is a technology enthusiast up to a point.
But if there is one area that continues to cause him concern, it’s the general ability of readers to know what a good map looks like.
The goal of How to Lie With Maps is to introduce a healthy scepticism in the way that we read and create maps.
“I’m not as optimistic as I’d like to be [about the state of map literacy] . . . people are not concerned about understanding technology as long as it seems to work”.
He cites the example of choropleth maps — those that use different shades of lightness and darkness to represent intensity — as easy to create, but also easy to get wrong.
But while uninformed errors might lead to regrettable mistakes, Mr Monmonier is keen to point out that maps lie open to deliberate manipulation: “Machiavellian bias can easily manipulate the message of a choropleth map . . . the white lies of map generalisation might also mask the real lies of the political propagandist”.
He talks about maps where readers are “very easily impressed by large areal units that may have relatively few people.
So when they look at a national map of the US where we have some states with relatively low populations — Montana, Wyoming and Idaho — they obviously create a much greater impact than, say, Massachusetts [which is smaller but has a greater population]”.

This seems like the right time to bring up a particular map now hanging in the White House.
Last year, Trey Yingst of the One America News Network tweeted a picture of a county-level map of the 2016 US presidential election heading into the West Wing.
It shows America predominantly Republican red with just small pockets of Democrat blue. Monmonier suggests the map “plays to the mindset of our president.
The fact is that Trump lost the popular vote by millions of votes — but the map doesn’t show this.
It needs to be balanced by another map”.
The cartographer Kenneth Field has done just that.
Using the same results data, he used dots to represent voters instead of continuous shaded areas to represent voting regions.
The difference is profound — Field’s results map looks a lot less red.
It is a stark example of the influence a cartographer can exert over a naive map reader.

Uses of maps for political propaganda are not new: How to Lie With Maps includes a German map from 1940 that portrays the UK as the aggressor in world war two.
More recently, observers have noted how China has adopted a new map projection that no longer requires distant disputed waters and islands of the South China Sea to be framed in an inset.

 'A Study in Empires' from from Facts in Review 2, no. 5 [February 5, 1940]

Mr Monmonier’s book also cites maps produced by the media as being particularly prone to “cartographic glitches”.
So, perhaps somewhat riskily, I finish our discussion by asking him for his thoughts on maps produced by the FT.
He promises to review and respond by email.
After a nervous wait, the professor’s opinion arrives “Excellent maps . . . I shared them with my map design class on Friday”.
With academic credibility conferred, I decide that now might be the time for us to step readers through the FT’s map design process.

Links :

• FT : Data visualisation: how the FT newsroom designs maps
• CityLab : When Maps Lie
• National Geographic : How to Make Maps and Influence People
• CityMetric : Paper towns and trap streets: when mapmakers get it wrong on purpose
• The Economist : X marks the spot
• GeoGarage blog : Advisory notice on "Web Mercator" / Mercator projection : the Greenland problem / Lies, damned lies and maps / Ancient maps show islands that don't really exist / Improbable South Pacific reefs / South Pacific Sandy Island 'proven not to exist' / How a fake island landed on Google Earth / These imaginary islands only existed on maps / About the Null island at 0°0'0" N 0°0'0" E